Many kinds of removable band-type couplings for pipes exist in the art. It is noted that throughout the specification and claims, the term “pipe” encompasses any kind of generally cylindrical object.
For example, one commercially available type of pipe coupling has a seal clamp housing. Clamp members are positioned face to face and a tightening element is tightened to press an annular seal element against the outside of the pipe inserted through the seal clamp housing.
In this type of pipe coupling, the seal has integrally formed rings at opposite ends of its axial length. The pipes that are inserted in the coupling contact these rings. The inner diameter of the rings can be adjusted to accommodate different outer diameters of pipes. The seal has an axial split along its length. The edges of the seal along the split either abut each other or overlap, and are pressed against each other when the coupling is tightened on the pipes. However, the rest of the axial length of the seal between the rings is thinner than the rings and does not contact the outer diameters of the pipes inserted in the coupling. Since the pipes do not contact the seal along most of the split, a problem can possibly occur wherein the edges of the seal along the split are not adequately pressed together to form the desired fluid-tight seal.